Relevancia del síndrome piramidal en la esclerosis lateral amiotrófica

Synaptic dynamics linked to widespread elevation of H-reflex before peripheral denervation in amyotrophic lateral sclerosis

Changes in Hoffmann reflex (H-reflex) exhibit heterogeneity among patients with amyotrophic lateral sclerosis (ALS), likely due to phenotype diversity. Current knowledge primarily focuses on soleus H-reflex, which may demonstrate an initial increase before subsequent decline throughout the disease course. The main objective was to investigate other muscles, to determine whether H-reflex changes could be associated with patient phenotype (onset site, functional disabilities). Additional experiments were performed to elucidate the neurophysiological mechanisms underlying H-reflex modifications. In age- and sex-matched groups of control subjects and patients, we compared H-reflex recruitment curves in soleus, quadriceps, and forearm flexors. Additionally, we examined H-reflex and motor evoked potential (MEP) recruitment curves in quadriceps. Last, to assess potential changes in monosynaptic excitatory postsynaptic potentials (EPSPs) of both peripheral and cortical origins, we analyzed peristimulus time histograms (PSTHs) and peristimulus frequencygrams (PSFs) of single motor units, along with H-reflex occurrence after paired-pulse stimuli. The ratio between maximal amplitudes of H-reflex and direct motor response increased in all muscles, irrespective of disease onset, and was found positively correlated with exaggerated osteotendinous reflexes and spasticity but depressed in patients on riluzole. This finding was accompanied by a reduction in MEP size and no changes in PSTH, PSF, and paired-pulse H-reflex probability. It is speculated that spinal interneurons may compensate for potential depression of monosynaptic EPSPs in ALS. From a clinical perspective, although the added value of H-reflex to osteotendinous reflex evaluation may be limited, it can serve as a valuable quantitative biomarker of pyramidal dysfunction in clinical trials.NEW & NOTEWORTHY Without significant evidence of peripheral denervation, H-reflex enhancement appears to be a widespread phenomenon, regardless of disease onset site. This increase is likely associated with a decrease in inhibitory control over presynaptic transmission of the synapse between muscle group Ia afferents and motoneurons. Although the link to exaggerated osteotendinous reflexes and spasticity implies a restricted role in identifying a pyramidal syndrome, its quantitative aspect positions the H-reflex as a valuable biomarker in clinical trials.

Surviving critical COVID-19: How functionality, physical, mental and cognitive outcomes evolve?

PURPOSE

To analyze the long-term consequences of critical COVID-19, regarding physical, mental, cognitive and functional impairments, and to describe its evolution through time.

METHODS

Prospective cohort study, with consecutive inclusion of patients admitted due to SARS-CoV-2 to intensive care units(ICU) of a tertiary-care center, between May/2020 and September/2021. All included patients were included in Physical and Rehabilitation Medicine(PRM) inpatient programs during ICU stay. Eligible patients were evaluated on PRM appointments 6 and 12 months after ICU discharge. In each visit, physical examination and a predefined set of scales were applied, aiming to comprehensively evaluate the three domains (physical, mental and cognitive) of post-intensive care syndrome and the patients' functionality. Statistical analysis encompassed descriptive and univariate analysis.

RESULTS

A total of 42 patients were included: 66.7% males, mean age of 62 yo. In the physical domain, 6 months after ICU discharge, there was a significant reduction in quality of life (p-value = 0.034), muscle strength (p-value = 0.002), gait ability (p-value<0.001) and balance (p-values<0.001) and increased fatigue levels (p-value = 0.009), in comparison with reference values. Yet, a significative positive evolution was observed in all referred subdomains (p-values<0.05). Nevertheless, 12 months after discharge, muscle strength (p-value = 0.001), gait (p-value<0.001) and balance (p-value<0.001) were still significantly compromised. Regarding the mental domain, both at 6 and 12 months after discharge, the levels of anxiety and depression were significantly increased (p-values<0.001). Nonetheless, a positive evolution was also found (p-values<0.02). Cognitive performance was significantly impaired in comparison with reference values, both at 6 and 12 months (p-value<0.001). Yet, a global improvement was also depicted (p-value = 0.003). Six months after ICU discharge, 54.8% were autonomous in activities of daily living, a value that improved to 74.0% in the subsequent 6 months (p-value = 0.002).

CONCLUSION

Critical COVID-19 survivors present significant physical, mental and cognitive impairments 6 and 12 months after ICU discharge, despite their positive evolution through time.

Prevalence of spasticity and spasticity-related pain among patients with Amyotrophic Lateral Sclerosis

Although they are common symptoms of ALS, there is little information on the prevalence of spasticity and spasticity-related pain. Consecutive patients were prospectively recruited from an ALS referral center. Clinical assessment, functional scores, features of spasticity-related pains has been recorded. In a cohort of 150 patients, 36% presented with spasticity. Spastic patients were younger, with a longer duration of disease. Spasticity accelerates the functional decline of patients. Spasticity-related pain was reported in 42.5% of spastic patients with mild pain. However, 16.7% of spastic patients presented significant pain with numeric rating scale≥4. More clinical trials are needed to treat spasticity more effectively and to relieve ALS patients.